Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for HD 189733: 07-25 (100), 07-26 (100), 07-27 (100), 07-28 (100), 07-29 (100) — by astronomy; check the weather when the night is within four days.

2035-07-20astronomy score per night — click a bar for that night2035-08-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-07-20 Fri	36	—	unknown	22:55–04:05 (marginal, 5.17 h)	71.1° 01:30	5.22	100%	39.7°
2035-07-21 Sat	40	—	unknown	22:50–04:10 (marginal, 5.33 h)	71.1° 01:25	5.26	98%	40.9°
2035-07-22 Sun	49	—	unknown	22:50–04:10 (marginal, 5.33 h)	71.1° 01:20	5.31	94%	44.9°
2035-07-23 Mon	63	—	unknown	22:50–00:55 (good, 2.08 h)	71.1° 01:15	5.36	89%	51.2°
2035-07-24 Tue	98	—	unknown	22:50–03:20 (good, 4.5 h)	71.1° 01:15	5.41	82%	59.1°
2035-07-25 Wed	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.46	73%	68.1°
2035-07-26 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.52	63%	77.9°
2035-07-27 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:00	5.57	52%	88.2°
2035-07-28 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 01:00	5.62	41%	98.8°
2035-07-29 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.67	30%	109.5°
2035-07-30 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:50	5.73	20%	119.7°
2035-07-31 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.78	11%	129.0°
2035-08-01 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.84	5%	136.3°
2035-08-02 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.89	1%	140.1°
2035-08-03 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:35	5.95	0%	139.4°
2035-08-04 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	6.0	2%	134.6°
2035-08-05 Sun	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:25	6.06	7%	127.0°
2035-08-06 Mon	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.12	13%	118.0°
2035-08-07 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.17	22%	108.4°
2035-08-08 Wed	100	—	unknown	22:20–04:35 (good, 6.25 h)	71.1° 00:15	6.23	31%	98.6°
2035-08-09 Thu	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:10	6.29	40%	88.9°
2035-08-10 Fri	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:05	6.34	50%	79.5°
2035-08-11 Sat	100	—	unknown	22:15–04:40 (good, 6.42 h)	71.1° 00:05	6.4	60%	70.4°
2035-08-12 Sun	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 00:00	6.46	69%	61.9°
2035-08-13 Mon	96	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 23:55	6.52	77%	54.1°
2035-08-14 Tue	90	—	unknown	00:05–04:45 (good, 4.67 h)	71.1° 23:50	6.57	85%	47.5°
2035-08-15 Wed	84	—	unknown	03:55–04:45 (good, 0.83 h)	71.1° 23:45	6.63	91%	42.5°
2035-08-16 Thu	55	—	unknown	04:45–04:50 (good, 0.08 h)	71.1° 23:45	6.69	96%	39.9°
2035-08-17 Fri	41	—	unknown	22:05–04:50 (marginal, 6.75 h)	71.1° 23:40	6.75	99%	40.2°
2035-08-18 Sat	43	—	unknown	22:05–04:45 (marginal, 6.67 h)	71.1° 23:35	6.8	100%	43.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-07-20&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.